In a conventional glass fiber forming process, continuous filament glass fibers are produced by drawing molten glass at a high rate of speed from tips of small orifices in a precious metal device or bushing. The fibers are gathered together to form one or more bundles or strands which are wound upon a rotatable collector, such as a forming or collecting tube mounted upon a rotating cylinder or collet of a winder.
To initiate the fiber forming process, an operator pulls the fibers from the bushing and groups them together to form one or more strands. To protect the glass fibers from interfilament abrasion, a sizing composition may be applied to the surface of the fibers during the forming process. Generally, the sizing composition is applied to the glass fibers subsequent to fiber forming and prior to gathering of the strands on the collecting tube.
After application of the sizing composition, each strand is passed over a gathering guide and wound around one end of the collet beyond the collecting tube. The collet and collecting tube are rotated and, when the proper drawing speed is attained, the strands are bundled together and moved onto a traverse, for example, a spiral wire traverse as shown in U.S. Pat. No. 4,239,162 and K. Loewenstein, The Manufacturing Technology of Glass Fibers, (2d Ed. 1983) at pages 188-190, which is hereby incorporated by reference.
A variety of traverse mechanisms including a pivotable traverse arm have been proposed for winding a single strand or thread onto a rotating collector. For example, U.S. Pat. No. 3,169,717 discloses a primary traverse mechanism for traversing a strand comprising an oscillating strand engaging member or bar. The bar may be U-shaped or curved.
When multiple strands are wound into a forming package, slight differences in tension between the strands and tension changes arising from changes in geometry resulting from the rotation and stroke of the traverse may cause some strands to adhere to and overlap each other, causing difficulty in unwinding and separation of the strands.
For traversing a plurality of strands, U.S. Pat. No. 3,438,587 discloses an apparatus and method for winding a curtain of filaments onto a rotating collector. The apparatus includes rotatable probes which traverse the package parallel to the rotational axis of the package. The probes are pivotally adjustable to alter the position of the probes relative to each other.
U.S. Pat. Nos. 4,488,686, 4,509,702 and 4,538,773 disclose a traversing guide for winding a plurality of strands. The guide traverses the package parallel to the rotational axis of the package. The traverse guide has angularly opposing sides that converge to meet and extensions protruding each side to subtend partially the point of convergence of the opposing sides.
In a typical winding operation, the strands are reciprocated by the traverse over a length of the tube to wind the strands in a predetermined pattern lengthwise along the rotating tube to form a forming package. Typically, at least one of the spiral traverse or the collet is also reciprocated in a direction parallel to the central rotational axis of the collet.
The forming package may be dried at room temperature or heated in a drying oven to remove excess moisture and cure any curable component of the size, if present. The strands may be unwound from the package and combined in parallel form to form one or more rovings or wound upon a bobbin for use as a yarn in weaving.
The problem of winding a plurality of strands into a package in such a manner as to facilitate removal of the strands, mitigate overlapping and adhesion between the strands, reduce catenary and friction and strand breakage in the forming process has not been adequately resolved in the art.